Remote Investigation of Total Chromium Determination in Environmental Samples of the Kombolcha Industrial Zone, Ethiopia, Using Microfluidic Paper-based Analytical Devices.

Microfluidic paper-based analytical devices (µ-PADs) fabricated in Japan were employed for the determination of total chromium (Cr) in water, soil, and lettuce irrigated with wastewater in Ethiopia. The µ-PADs, which were printed by wax printing in Japan, were transported to Ethiopia and prepared for the determination of total Cr by adding appropriate reagents to the pretreatment and detection zones. Soil and lettuce samples were determined by the µ-PADs and a UV-Vis spectrophotometer in Ethiopia. A paired t-test showed that the mean total Cr concentrations determined in the soil and lettuce samples were not significantly different between µ-PADs and UV-Vis spectrophotometric analysis at the 5% level of significance. This implies that the µ-PADs have good accuracy and reliability, and could be employed to monitor Cr in environmental samples. We found that the total Cr concentrations in all soil and lettuce samples were above the permissible limit. Moreover, evaluating Cr contamination level using the geo-accumulation index indicated that the soils were contaminated with Cr moderately to heavily. Thus, the present work successfully demonstrated the potential of remote investigations of pollution in a less-equipped laboratory by transporting the µ-PADs fabricated in another laboratory.

Identification of race-associated metabolite biomarkers for hepatocellular carcinoma in patients with liver cirrhosis and hepatitis C virus infection.

Disparities in hepatocellular carcinoma (HCC) incidence and survival have been observed between ethnic groups including African-Americans (AA) and European-Americans (EA). The evaluation of the changes in the levels of metabolites in samples stratified by race could provide a snapshot of ethnically diverse disease related pathways and identify reliable biomarkers. In this study, we considered AA and EA to investigate metabolites that may be associated with HCC in a race-specific manner. The levels of 46 metabolites in plasma samples, collected from patients recruited at MedStar Georgetown University Hospital, were analyzed by Agilent GC-qMS in selected ion monitoring (SIM) mode. A least absolute shrinkage and selection operator (LASSO) regression model was applied to select metabolites with significant changes in HCC vs. cirrhosis in three groups: (1) AA and EA combined; (2) AA separately; and (3) EA separately. In addition, metabolites that distinguish HCC cases from cirrhosis in these three groups were selected by excluding those without HCV infection. The performances of the metabolites selected by LASSO in each group were evaluated through a leave-one-out cross-validation. We identified race-specific metabolites that differentiated HCC cases from cirrhotic controls, yielding better area under the receiver operating characteristics (ROC) curve (AUC) compared to alpha-fetoprotein (AFP), the serological marker widely used for the diagnosis of HCC. This study sheds light on metabolites that could potentially be used as biomarkers for HCC by monitoring their levels in high-risk population of cirrhotic patients in a race-specific manner.

Concentration levels of essential and non-essential metals in Ethiopian khat (Catha edulis Forsk).

The levels of essential (Ca, Mg, Mn, Fe, Zn, Cr, Cu, and Co) and non-essential (Cd and Pb) metal in six different varieties of Ethiopian khat (Catha edulis Forsk, an evergreen stimulant plant) commonly consumed in the country and exported to the neighboring countries were determined by flame atomic absorption spectrometry. Known weight of oven-dried khat samples were wet-digested using 2 mL of (69-72%) HNO(3) and 2 mL of (70%) HClO(4) for 2 h and 30 min at variable temperature (120-270°C). The mineral contents in the digests were analyzed using flame atomic absorption spectrometer. The following concentrations ranges in fresh-weight basis were recorded in decreasing order: Ca (1,038-2,173 µg/g) > Mg (478.2-812.3 µg/g) > Fe (53.95-82.83 µg/g) >Zn (5.18-9.40 µg/g) >Mn (6.98-8.66 µg/g) >Cu (1.85-5.53 µg/g) > Cr (0.66-3.47 µg/g) >Co (0.41-0.80 µg/g). A wide variation in the mineral contents of khat from different region of Ethiopia was noticed. The toxic metals (Pb and Cd) were not detected in all the samples analyzed.